


The Nature of Breathing

by 401



Category: Captain America (Movies), Captain America - All Media Types, Iron Man (Movies), Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: Anal Sex, Dom Tony Stark, Dom/sub Undertones, Fluff and Smut, Friends to Lovers, Humiliation, Humiliation kink, Light Dom/sub, M/M, Oral Sex, Praise Kink, Steve Rogers Feels, Sub Steve Rogers, Tony Feels, Truth Serum
Language: English
Status: Completed
Published: 2018-12-18
Updated: 2018-12-18
Packaged: 2019-09-22 06:15:40
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,795
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17054708
Author URL: https://archiveofourown.org/users/401/pseuds/401
Summary: Steve accidentally drinks 'truth serum' meant for interrogation.Now, Tony knows everything.





	The Nature of Breathing

**Author's Note:**

> I hope I did okay on this one, I doubted it a million times whilst writing it.

Steve prided himself on honesty.

He considered it one of his best traits, perhaps even his favourite. When he thought about it, he couldn’t truly remember the last real _lie_ he had told _._ Sure, he had things that he just plainly didn’t mention, things that he decided were safer or more comfortably kept to himself, usually to avoid complication, but he never lied in the true sense of the word. If he was directly asked something, no matter how uncomfortable, he was inclined to frankness and openness. It was, in his mind, the only way he could expect the same from other people. Right under liars, in his eyes, were hypocrites.

He remembered lying as a kid.

 _“Steve, baby, are you_ sure _you’re well enough to go…”_

_“Yes, ma. Promise.”_

Steve would have thought with amusement at the memory of him clutching onto the edge of the ice rink he had been begging to go to all Christmas break, wheezing so hard that his throat burned, and his lips turned blue, all the while maintaining that he was ‘absolutely fine’, but he was preoccupied.

Preoccupied by trying not to spill every secret he had ever kept all over the emporium of chrome and glass that was Tony’s kitchen.

“Bruce, how long is this going to last?” Steve whispered, as if keeping his voice low and small would protect him from the onslaught.

Banner bit his lip and sighed, suppressing a grin. He raked a hand over his face and sat down at the bar.

“Probably till around tomorrow morning?” He estimated, “It lasts about 3 days in a normal person, at the dose you took. You might still be overly…open for a day or so after that. Nowhere as much as _this_ , though.”

Bruce gestured to Steve generally.

“It’s really pissing me off that you’re smiling right now, which is horrible because you are one of the most genuinely lovely people I have ever met, but I want to punch you square in the face right now, because you’re smiling,” Steve blurted out.

Bruce’s face was one of bewildered amusement. He bit his tongue and chose his words carefully. The least he could do for the Captain was avoid any leading questions, anything that could open any metaphorical cans of worms.

“Well,” He cleared his throat, “Thank you, and please don’t. I think we both know how that would end.”

Steve groaned and let his head slump against the table.

“I don’t really want to hit you,” He sighed, “I’m just scared that I’m going to tell all of my friends and colleagues my deepest, darkest secrets. It’s making me feel insecure and exposed like I’m naked. I actually have a real problem with being naked in front of people. I’ve never mentioned it,” he rambled out.

It was like sneezing. Or vomiting. Projectile and unavoidable. The usually well managed link between his brain and his mouth had been severed. If it passed through his head, it came out. Water through his fingers. Steve wished that he _was_ vomiting or sneezing; at least then he wouldn’t be speaking.

Tony’s lab was a notoriously disorganised place. He operated seamlessly in chaos. Things didn’t always have labels, bottles were often similar and sporadically placed and the surfaces were usually covered in an hundred different projects at various stages of completion. Steve wondered whether Tony had put his prototype for a government strength ‘Interrogation Solution’ next to his prototype for a calorie shake that Steve wouldn’t burn through in fifteen minutes on purpose, but he hoped that his suspicion was incorrect. 

He had felt fine, no different at all, until he had gotten into the elevator with Nat. The words had spilt out of his mouth like they were someone else’s.

“When you blush when you’ve been training, it makes me wonder if that’s what you look like during sex. I don’t even particularly want to have sex with you, it would be weird; like having sex with a cousin or something, I just picture it when you’re all sweaty.”

Nat had stared for a long while at the beet-red captain, mouth just slightly slack.

“What…what cup did you pick up, Steve?”

“The little one. Those calorie solutions always taste like crap, so Tony tries to make them as small as possible for me,” Steve muttered, “Don’t tell him I said they taste like crap, the strawberry one was pretty good. Eating every half an hour was just getting old. I really care about Tony’s pride, so don’t tell him it tasted like sh…”

“Oh my god,” Nat whispered.

“What?”

“You drank the truth serum…you drank the IS:42,” She grinned, “Oh my God, Steve. Go to bed, please, for your own…dignity.”  


Steve had stared at the glossy wooden floor of the elevator in silence until Natasha’s stare had started to burn.

“Don’t tell Tony,” he finally managed, “Please.”

Nat’s face morphed slowly into one of mischief.

“Why not?” She asked knowingly.

Hopelessly, Steve spectated as his mouth opened and he started speaking.

“Because I’ll tell him that his laugh is obnoxious, that when he is angry it turns me on and that whenever we spar I get hard to the point where it is uncomfortable. I literally have to masturbate after I spar with him otherwise I can’t concentrate all day.”  


Steve let out a shaky breath and squeezed his eyes shut.

“Nat, knock me out please,” He whined, “Do the sleeper hold thing.”

 

“Not a chance. JARVIS? Call Tony and tell him to meet us in the kitchen please,” Nat giggled at the ceiling.

 

“Natasha, you _bitch_ ,” Steve hissed, “Oh my God, I’m so sorry, that was disgusting. I don’t even like that word, _fuck_. Why am I cussing, Nat? I don’t like this, I don’t like this one bit.”

 

So now, he was in the kitchen of Stark Tower, hot with shame and willing his brain to stop racing. Every thought that passed threatened to climb from between his lips and dig him deeper into the hole of dread that he was sitting in. He was pulled quickly and unceremoniously from the relative safety of his silence by Tony skipping into the room.

He was grinning. Steve was not.

“Steve,” He almost shouted, “Who’s your favourite Avenger?”

“Sam,” Steve answered, “He’s the only person out of all of us who isn’t a walking ball of drama.”

 

“Oh my God, it works,” Tony whispered, clasping his hand to his mouth and smiling like a proud father.

 

“I love that face,” Steve mumbled, “I love seeing you proud of the things you create. It’s adorable. I wish you did it more.”  


Bruce chuckled, and Natasha pushed the sleeve of her sweatshirt to her pursed lips, staying silent. The doctor had sat back in his chair as if he were settling in to a good film. Tony crossed the room and took a seat at one of the breakfast stools.

“Do continue,” He coaxed, “You can massage my ego if you want. For science.”  


“I doubt it needs massaging, but I think you only act arrogant because you think you aren’t actually good enough. Probably because of your dad.”

Tony raised his eyebrows.

“Um, ouch,” He hissed, biting down on a laugh, “A little less, maybe.”

 

“I _would_ like to give you a massage though. You’ve got me thinking about that now. Touching you. I’d like to see that, get you all calm and blissed out.”

 

Tony’s mouth fell open a little and his eyebrows knitted together.

 

“Maybe you’d actually sit still for a minute, get some sleep even. God, I worry about you so much when you go on those long…at least if you were asleep then you wouldn’t be making any fucking truth serums, Tony _why??_   Why would you make this?”

Steve had settled with the fact that the heat in his face was not going to subside, and that it was glaringly obvious. He had hit the numb peak of embarrassment where anything could happen, and it would probably make no difference.

“This is getting good,” Bruce chuckled, “This is getting _juicy._ Nat what did you call good gossip the other day? Sauce...?”  


“Tea.”  


“That’s it. This is good tea.”

 

“You should’ve heard him in the elevator,” Nat muttered, crossing her legs but not looking up from her phone.

 

“NO,” Steve shouted, “No, no, _no_.”

 

“Why don’t you tell us what you said in the elevator, Steve? About Tony?” She grinned.

 

Steve balled up his fists and battled against the pressure in his throat. It really was like trying not to vomit. Steve thought that he _might_ vomit, the heat that had spread across him was so pervasive and overwhelming. The pressure turned to an itch, and then and unbearable burn. Steve let out a yelp as he opened his mouth.

 

“I get hard when I spar with Tony. Seeing him get sweaty really turns me on. I have to jack off after most of our sessions.”

Bruce was shivering with laughter now, tears streaming down from behind his glasses. He at least tried to hold it back, Natasha was sitting back and looking Steve dead in the eyes, a grin curling on her mouth and her shoulders shaking.

“I should be documenting this,” Bruce finally hooted when he could manage to breathe, “Steve, I’m so sorry. For science.”  


Tony bit his lip and frowned, uncharacteristically quiet and speechless for the first time in years. He felt himself blushing, and he wished it was only second-hand embarrassment. That would be something he could laugh about. He could have teased Steve about that, brought it up as some anecdote. This was different. This was excitement.

“A-anything else on your mind there, Captain,” he asked, his voice suddenly small.

Steve pulled a face of tortured resignation before his bottom lip quivered. For a moment, Tony felt terrible; Steve looked as if he might burst into tears at any moment. Instead, he gritted his teeth and squeezed his eyes shut. It did not work. The words burst out harder and louder than they might have otherwise, and his voice cracked and flexed of its own accord, like the stressed branches of a tree that had been tethered by a great weight. The release gave nothing but a recoil, harsh and messy.

“Seeing you every day and not being able to tell you how I feel is killing me,” Steve shouted, surprised at the volume of his own voice, “I love you, I’ve stopped doubting that now, I stopped a while ago.”

 

Tony nodded slowly. The admission echoed in his head.

“Bruce,” He said quietly, “Could you note down that the neural inhibition override we tried works great, and then maybe…give us a minute? Please?”

Bruce nodded and smiled nervously. The air and atmosphere in the room had condensed and was now thick and cloying.  The doctor stood slowly and beckoned Natasha to follow, reserved shock painting her features. She rubbed Steve’s shoulder as she left the kitchen.

“That wasn’t even remotely comforting,” He said flatly, no energy left to mask or soften the bluntness with which the statement fell.

She breathed a laugh and planted a kiss on Steve’s forehead.

“You were ready,” She shrugged.

She shot a wink at Tony before leaving the room and leaving the pair in silence.

 

“Please don’t ask me anything else,” Steve pleaded, “I’ve embarrassed myself enough for one day.”  


“Go and sit on the couch,” Tony ordered numbly, “I’ll make you a coffee. I think I owe you that, at least.”  


Steve sighed and mouthed a thank you, not trusting his voice. He tried to slow the rapid undulation of his thoughts while he waited, listening to the sounds of clattering cups and the thrumming of the coffee machine. He tried everything. Visualisation, mindfulness, plain old self-reprimand, but it all just brought more confessions to the tip of his tongue. However he felt, he could not deny that this stuff _worked._ But Tony had made it; he couldn’t really be surprised.

He was surprised when Tony returned wearing a very genuine, mischief-free smile on his face. He set down two coffees and slumped onto the couch.

 

“Why have you never told me any of this?”

 

Steve hesitated, realising that he genuinely didn’t have a straight answer.

 

“We had a team to manage,” He finally explained, “I couldn’t get in the way of that. If my feelings get in the way and something goes wrong…that’s on me. I can’t risk that.”

 

“What else,” Tony asked.

 

“I’m…I hate being vulnerable, Tony. If I let myself, I’d be putty in your hands. You could manipulate me in any way you wanted. I’d probably love it too, that’s the worst part. You have no idea what you do to me, emotionally, physically. I’m scared of it.”

 

Tony pulled a face that was something like pity, something like frustration. Steve couldn’t be sure. He leant across the space between them and cupped Steve’s cheek. The pained frown remained on his face.

 

“You’re an _idiot_ , Steven.”

 

“I know.”

 

Tony smiled crookedly, stealing the air right out of Steve’s lungs like he always did. He stared at him, unable to pull his gaze away. The man was enthralling, and this was the closest Steve had ever gotten to him. In all their years of working together, Steve had never gotten to see the details. The streak of grey at his hairline, the way his eyes were much closer to hazel than brown, the crows-feet wrinkles at the corners of his eyes. Steve felt more words bubble up in his throat and he did nothing to stop them.

 

“I should have kissed you years ago,” Steve whispered, “I should have loved you like you deserve every day up till now. I’m sorry.”

 

Tony groaned as if weight had been released from him. Steve knew that feeling, the aching lightness when you have been squashed for so long. He pulled Steve roughly, by the collar, locking their lips together and anchoring him in place with a firm hand on the back of his neck. The kiss was harsh but tender, an ‘I’ll be damned if you don’t feel loved’ kind of kiss, a kiss that had built up for too long until it had changed from a gesture to a necessity.

Steve relaxed into it because now, he was not in the mood to be treated gently. Tony could kiss him until he passed out for all he cared. He craved the silence of being utterly absorbed. The pinpoint pressure of fingers dragged down Steve’s spine, dipping just under the hem of his t-shirt, grazing his hip just enough to give him goosebumps. The winding knot of need and restraint in his chest tightened and he pressed into the touch. He pressed into heat and need and the beckoning lull of just letting go. On cue, Tony said the words that cut all of Steve’s strings.

 

“Tell me what you want.”

 

The first sound Steve made was not a word. It was something choked and needy. A growl? All he knew was that it was a visceral and instant reaction to the images that sprung behind his eyes in response to the demand.

 

“I want you to kiss me harder,” Steve croaked, “And I don’t want clothes between us. It’s driving me crazy that I can’t feel your skin.”

 

 

  


 

Tony nodded, looking down at his watch and pressing icons on the screen. The light in the room got less jarringly bright and the doors made a clicking noise that Steve could only assume was them locking. The floor to ceiling windows tinted automatically and everything suddenly felt smaller. Steve was too hazy to be astounded by it today. He would get Tony to show him how it worked in the morning.

 

“Keep talking.”

 

Tony’s voice was rough, the hazel in his eyes that Steve had been so transfixed by was just a rim of reseda around blown pupils. He parted Steve’s lips with his tongue as he kissed him again and nipped the bottom one so that his words were huffed into his mouth instead of spoken.

 

“I want you to fuck me,” Steve whined involuntarily.

  
Tony moaned gently.

 

“I want you to fuck me while I’m still humiliated. I have a thing about that. Is that a kink or a fetish? I don’t know the difference. I want it though, I want you to make me feel exposed,” He continued, squirming at the frankness of his own words.

 

Tony pulled him closer, dragging his fingers through his hair and moving his mouth to his throat, sucking bruises that he knew people would be able to see, that he knew Steve would fuss with trying to cover until they faded. Steve’s breathing climbed, and he wrapped his arms around him, the heat of their bodies lying flush overwhelming him for long enough that he could find words in the soup of pictures and feelings that was slowly drowning him.

 

“Clothes, Tony,” he managed to whisper, “ _Please_.”

 

Tony chuckled breathlessly and pulled his t-shirt over his head, chucking it onto the coffee table before repeating with Steve’s. He moved back quickly, not wasting any contact before this would all inevitably have to end. He tried not to think about it, an end to Steve. It was like anticipating an end to breathing at this point. It struck longing and anxiety into him that he did not welcome.

 

“You’re beautiful,” Steve mumbled against Tony’s chest, “You don’t know it, but you are. You’re too hard on yourself, all the time. It hurts me that you don’t see what I see.”

 

“This stuff was designed to get criminals to spill their guts, not to get you to make me cry, Rogers,” Tony sighed.

 

Steve coughed out a laugh and breathed an apology. He distracted his mind by exploring, trailing his hands over Tony’s back, his chest, his neck. Anywhere that his fingertips could reach, he wanted. A flush was spreading over Tony’s cheeks that Steve had never seen before. It made an almost invisible dusting of freckles stand out and for a moment, Steve felt like he might cry himself. The empty space that he had been ignoring for so long was now overflowing and the energy needed to go somewhere. 

 

He sat up for a moment, shuffling his jeans off, going to fold them before thinking better of it. Tony sat back and watched, brow knitted with concentration and awe, before snapping back and taking off his own, again wasting no time before pushing them back together.

 

“Do you want to be on top?” He asked.

 

“No,” Steve replied, “No, I don’t.”  


Tony nodded and pulled Steve’s hips to his sharply, hearing him gasp and buck into the friction needily. He caught the advance, pinning him to the couch with more force. This was a thrill to him, being able to control someone who he had seen completely dominate combat. He only had to use the lightest of touches, but the control was absolute. Steve melted into it like he was made of rubber, his eyelids flickering as Tony threatened, just threatened, to push against his throat, ghosting his fingers just enough to suggest the pressure.

“ _Please,”_ Steve begged, his voice pitchy and strained.

 

Tony stood up, a grin on his face that Steve wanted to kiss off of it. He stayed where he was, in front of Steve, carding through his hair slowly, tracing the line of his jaw, tugging his hair gently when he could see his focus slipping. Steve battled with the urge to squirm, planting his feet on the floor to stop his legs shivering.

 

“You’re pretty,” Tony mumbled, “So pretty, too pretty.”

 

“I…I don’t feel it. A lot of the time,” Steve managed to cough out between numb lips.

 

Tony shushed him gently, moving his hand to his cheek and brushing his thumb over the flushed skin. He slid his boxers to the floor in a smooth collected movement that Steve knew he wouldn’t be able to match. When he did it, his hands shook, they got tangled around his ankles and he resorted to kicking them off. Tony smiled at the endearing urgency before pulling Steve closer, off of the couch and onto the floor, kneeling before him.

 

“Open your mouth,” he ordered hoarsely.

 

Steve obeyed, closing his eyes and letting his mouth fall open. It felt surprisingly natural, as if the chemicals running through his blood were untying his body as well as his mind, making him loose and pliable in so many more ways than one. Tony was gentler than he expected, not pushing his head but guiding it, muttering small reassurances and praises that shivered up his spine every time they were uttered.

More humiliation washed over him when he realised just _how_ much he was enjoying it. The slide of skin against his tongue, the intoxicating rhythm of it all, the way Tony looked down at him through his eyelashes with a positively debauched expression of lust and adoration, they all pulled at the fraying fibres of minimal self-control that Steve was still clinging to. He knew they would break, and the anticipation fuelled him. How far could he push himself? How far could he take this before all of the restraint he had built up for decades left him? Would it be freeing or terrifying? Steve guessed both. He would take them hand in hand.

 

“For someone who had been repressed since the Forties, you really know what you’re doing.”

 

Tony’s voice was breathless and only barely brought Steve back into the room. He sat back on his heels and looked down at the hardwood under his knees. Tony tilted his chin back up and eased him to his feet. He turned him round, all the while tracing the lines of his back, playing over the skin as if the touch was effortless and every bit of contact was not tearing him apart. Steve envied it but was beyond caring. He would work on relaxing when his whole body had stopped throbbing and he could think of anything besides being taken apart.

 

“Bend forward for me,” Tony whispered, “Arms on the back of the couch. Wait there, I’ll be back, I promise.”  


Steve nodded. He could do that. He could stay still, he could follow instructions. It was the first thing that he had done that day that had not taken all of his mental strength to carry out.

So, he waited, forehead to forearms, letting the room dissolve for a while and listening to the fevered cadence of his heartbeat, trying to ignore his aching hardness when it felt like he would break, touch or no touch.

 

“Sorry.”  The voice surprised him.

 

“I don’t usually do…anything in my kitchen. I’ll make a note to keep lube next to the oregano.”

 

Steve chuckled and brushed the apology away.

 

“You have a couch in your kitchen, that’s odd enough,” Steve pointed out.

 

Tony huffed a laugh, running his hands up the backs of Steve’s thighs as he squeezed the clear gel onto his fingertips in a beautifully practiced way that made Steve’s imagination twitch in its chains.

 

“Sometimes, when you’re making instant ramen at 3 am, you want to sit down. There’s nothing wrong with that,” he shrugged.

 

Steve just nodded, not wanting to open another stream of confessions. He didn’t want anything that would stand in the way of him being touched.

 

“You ready?” Tony asked.

 

“Yes, please.”

 

The lube was cold but was welcome respite where Steve was expecting to want to flinch away. It dulled the intimacy of it and put a slick, cool barrier between his skin and the invasive slide of fingers over his hole. The trembling in his legs started again, spiking more waves of hot embarrassment over his already burning skin. He whimpered something incomprehensible, even to himself, into the couch cushions, pushing back into the touch.

He _wanted_ Tony to comment on it. He wanted to be called out for his neediness. He wanted to be called names, names that would make him cringe in any other premise but that would sound like gospel if they were coming from Tony’s mouth. Instead he was met with sweetness and reassurance, reassurance that pleasure was coming, that his patience was good, that he was _good_. It mixed like honey in whiskey in Steve’s stomach, a potent cocktail that brought quick tears to his eyes once he realised that whatever Tony said fit his body like a second skin. He would be painted with words.

“I want you to be ready,” Tony said softly, “I’m not about to hurt you.”  


Steve nodded, throat tight with tears and muscles quivering with desperation.

 

“I don’t care if it hurts,” He choked, caught between a moan and a gasp.

 

Tony shushed him.

 

“I know you don’t, which is why I have to.”  


Fingers pushed into him, a sudden fullness more noticeable than Steve had expected. It was good, dull but good. One became two and gentle scissoring became a more and more sinful opening up. Steve found himself begging. The words left his mouth before he even thought to hold back, and they did not feel like his own. He knew they were though; he had never asked for anything with so much conviction in his life.

 

“Tony,” he gulped, “I can’t take… _fuck_.”

 

The fullness was overwhelming, the brink of painful that makes you pull away and push for more at the same time, like the deep knuckles of a massage on knotted muscles or the scrape of scratching an itch that had been building for too long.

Tony moaned as he thrusted, blunt fingernails digging into Steve’s hips as he coaxed him back, pulling him to and from him in circular arcs. Steve gripped the back of the couch and remembered what it was like to feel weak.

His spine felt gelatinous and his limbs begged to go limp and give in. It was all he could do to just hold on, closing his eyes and letting himself drown, breathing in great gulps of pleasure like it was air.

 

“Never hide from me again,” Tony groaned through gritted teeth, punctuated by thrusts, “I never want you to hide from me again.”

 

Steve felt as though he could never hide anything from anyone ever again, as open and searched as he was, but he kept quiet, breathing with the movement of hips and the sound of skin hitting skin. Tony’s fingers were in his hair, gripping until it ached and keeping him exactly where he was, as if he might float away at any given moment, and Steve had never been happier to be slightly uncomfortable in his life. He was sure it was the only thing keeping him from falling apart entirely.

 

“I’m sorry,” he panted, “I…”

 

Tony leaned forward, over his back, and pressed his lips to his ear. He held him as he sped up, stealing the words out of Steve’s mouth with well placed and devastating thrusts. Steve elected to ignore the sound that left his bitten lips and the change in angle and force.

 

“You’re close,” Tony whispered.

 

Steve nodded.

 

“You gonna’ come for me?”

 

Steve nodded harder.

 

“Good,” Tony breathed, “Good boy.”  


The praise was what did it. Steve’s vision greyed, the room darkened and every muscle in his body did something unfamiliar and addictive. He let himself whimper, he let himself choke over his words and he let Tony reassure him that it was exactly what he needed to do. He swallowed vulnerability like a stiff shot and let it burn, filling a cold, emptiness that he was tired of denying.

 

“Stay where you are,” Tony growled, “Stay right where you are, _fuck_ Steve, you’re perfect.”  


 

Thrusts lost all rhythm and Tony followed, bruising him with a desperate grip and biting down on his shoulder. Steve did not feel it.

 

It took a moment, but eventually the sound of their own thoughts managed to trickle back through the cracks of splintered pleasure and fill the space between them. Steve couldn’t remember falling into Tony’s arms, he couldn’t remember lying down on the couch, sweaty skin sticking to leather. He didn’t need to. He was present, as present as he ever had been.

 

“Steve,” Tony mumbled, hazy with sleep, “I love you, you know that, right?”  


Steve nodded against his chest, giving his hand a squeeze.

 

“And you love me?” Tony continued.

 

“More than anything.”

 

“Then please,” he whispered, “Never hold back again.”

 

Steve nodded. He didn’t think he could even if he wanted to, such is the nature of needing to breathe.

 

 

 


End file.
